CA1149287A - Sulfated anionic surface active agents - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An aqueous hair shampoo composition containing about 10 to 20% by weight of (1) an anionic surface active agent comprising a sulfated condensation product of ethylene oxide with a base formed by condensing propylene oxide with propylene glycol and having a molecular weight of about 1100 to 4800, the condensation product having the structure:
HO-(C2H4O)x(C3H6O)y(C2H4O)z-H
where y is an integer from about 30 to 70, and (C2H4O)x+z equals about 5 to 20% of the total weight of the compound, in combination with (2) about 5 to 15% by weight of a foam promoter comprising an amine oxide of the general formula:
R1R2R3N ? O
wherein R1 is an alkyl group containing from about 10 to 16 carbon atoms and R2 and R3 are methyl or ethyl groups.

Description

B~CKGROUND

This invention deals with novel sulfated condensation products of ethylene oxide with bases formed by condensing propy-lene oxide with propylene gylcol~ and having a molecular weight of about 110~ to 4800. T~e sulfated condensation products are useful as components in hair shampoo systems to provide an after-shampoo conditioning effect.
The primary function of any hair shampoo product is, of course, to thoroughIy remove from the hair accumulated deposits of sebum, airbbrne particulate materials, and residues of hair treating compositions such as hair sprays or other grooming aids. At least as important, however, from the standpoint of consumer satisfaction are the wet and dry combing properties of the hair a~ter shampooing and the feel and appearance of the hairO As a general rule, shampoos that thoroughly clean the hair tend to leave it hard to comb ancl in a dry, flyaway condition. Conversely, shampoos which avoid "over-drying" the hair, usually do so at the expense of cleaning effectiveness.
We have discovered a class of materials which when formulated with certain foam promoting agents as will be hereinafter detailed, yield compositions comparable to the better commercially available shampoo compositions in foaming and detergent activity. The compositions of the invention not only impart a smooth, scft feel to the hair, but combing, both wet and dry, is markedly improved~
The prior art describes in, for example, U.S. Patent

2,674,619, methods of ma~ing condensation products of ethylene oxide with bases formed by condensing propylene oxide with propylene gylcol. We s~lfate these condensation products to Tn c ~
,.

yield the no~el detergents of this i~vention. The 'prior art also discloses a family of polyoxypropylene glycol disulfate detergents described as superior heavy-duty fabric detergents having low foaming properties. These' materials are shown in .S. Patent 2,802,7890 Also shown in U.S. Patent 3,243,455 is a class of polyether hydroxy sulfonate surface active agents said to be useful in emulsi~ication and demulsification and as components in laundering compositions having good soil anti-redeposition properties. Nowhere'in the art, however, is there'disclosed the class of sulfated condensation products described herein or the use of such'products as components in hair shampoo compositions.
According to an aspect o~ the invention there is ' provided an aqueous hair shampoo composition containing about 10 to 20~ by weight of (1) an anionic surface active agent comprising a sulated condensation product of ethylene oxide with a base formed by condensing propylene oxide with'propylene glycol and having a molecular weight of about 1100 ta 48~0, the'condensation product having the structure:
20, Ho-(c2H~o)x(c3H6o)y(c2Hl~o)z-H
where y is an integer from about 30 to 70, and (C2H40)x+z equals about 5 to 20~ of the total weight o~ the compound, in combination with (2) about 5 to 15~ by weight of a foam promoter comprising an amine oxide of the general formula:
RlR2R3N ) O
wherein Rl is an alkyl group containing`from about 10 to 16 carbon atoms and R2 and R3 are each selected from the group consisting oi methyl and e-thyl groups.

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DETAILED DESC'RIPTIQN OF THE INVENTI'QN

The'class of condensation ~roduct precursors which are'sulfated in the practice of our invention is a we'll known class of nonionic sùrfactant polyols c~aracterized by high molecular we'ight predictability of behaviour and an extremely low order of toxicity~ the'molecule having hydrophilic groups at both ends of a variable hydrophobic base. Varying the' size of both the hydrophiles and the hydrophobe'permits the produetion of eompounds having a mix of properties tailored 0 to the needs of the formulating chemist.
Normally it would be'expected that the sulfation of such nonionic speeies to produce the corresponding anionic materials would result in an inerease'in skin and/o,r eye irritation levels when sueh'materials were employed as eomponents in aqueous hàir shampoo eompositions. We ha~e diseovered, however, that the partial or eomplete sulfation of eertain of such eondensation produets produees eosmetieally useful detergent materials retaining the advantageous irritation properties of the nonionic precursor.
The condensation products which we sulfate in the praetiee of our invention are those having the formula, HO-(C2H,IjO)x(c3H6o~y~c2Hl~o)z-H
where ry is an integer from about 30 to 70, ~referably about 40 to 6~, and (C~H40) X+2 equals about 5 to 20% of the total weight of the compound, preferably about 7 to 13%.
These materials are eommercially available in low HLB values of 1 to 4 and when sulfated and neutralized yield water soluble copolymers having an HLB range equivalent to

- 3 -sodium lauryl sulfateO ~92~7 The preparation of the nonionic surface active polyols which serve as the precursors for the.sulfated anionic surface active agents of this invention is well known in the prior art and is described, inter alia, in UOS. Patent 2,674,619~
The first step comprises the condensation of propylene oxide with propylene glycol to prepare a polyoxypropylene polymer of at least about 950 molecular weight. This polymer is ~hen condensed with ethylene oxide.
In the first step propylene oxide is condensed with propylene glycol to prepare the polyoxypropylene polymer as follows: ~

HO-eHCH2OH + CH ~ H-CII3 >HO(fHCH2OjyH

H.3 CH3 In the second step o the preparation, the polyoxy-ethylene chain is introduced into the molecule by condensation with ethylene oxide as follows:
~0~
HO(~HCH.. 2O)yH + C~ CH2- ~ HO-(C2H~O)x(C3H6O)y(C2HI!O)zH

In preparing the p~lyoxyethylene polymer the condensation of propylene oxide with propylene glycol is normally carried out at elevated temperatures and pressures in the presence of an alkaline catalyst such as sodium alkoxide, a quaternary ammonium base, or preferably sodium hydroxide.
Although the reaction may be carried out by simply heating the mixture of the reactants under pressure at a sufficiently high temperature, this procedure is not .~ - 4 -ms~

3'~37 ordinarily used as the temperature and pressures required are excessive and control of the reaction is difficult.
The preferred method of carrying out the reaction is to add the propylene oxide'to a stir,red heated mixture of the propylene glycol and alkaline catalyst in a sealed reaction vessel. By adding the propylene'oxide to the reaction yessel at such'a rate that it reacts as rapialy as added, an excess of propylene oxide'is avoided and control of the'-reaction~is simplified.
The condensation of ethylelie oxide'with the polyoxy-propylene polymer is carried out in an analogaus manner.
Partial or complete sulfation of the hydroxyl groups present in the'condensation products produced as described above 'is accomplished through'the use'of conventional sulfating agents such'as those used in the sulfation of fatty alcohol sulfates and their alkoxylated derivatives. These include the various known complexes of sulfur trioxide such as the complexes with dioxane,' trieth~lamine~ ammonia, and hydro-chloric acid. '~e prefer to sulfate by the slow addition of 2Q a hydroxy equivalent of chlorosulfonic acid to a methylene chloride solution of the condensed material. Water dispersible, surface active condensation products are obtained over the range of ~.5 to 2.~ moles of sulfating agent per mole of condensation product. ~here hydrophilic condensation products relatively high in ethylene oxide are to be sulfated, concentrations of sulfating agent at the lower end of the range should be employed to retain surface active properties.
The stirred reaction solution is cooled to prevent the temperature from exceeding 25C. Upon completion of the ms ~

Z8~7 addition~ the solution is sparged ~i~th nitrogen to remove any HCl which'is present. The'sulfuric acid ester is then conyerted to a salt by pouring the reaction mixture into an e~uivalent amount of stirred aqueous ammonia, amine or alkali or alkaline earth metal hydroxide. The pH'of the resulting emulsion is ad~usted to 8 to 9 with additional aqueous sodium hydroxide.
The organic solvents are then removed by distillation to yield a concentrated a~ueous solution of the sodium salt of the sulfated condensation ,roduct. The'ionic group of the surface active condensation product prepared as described above is the sulfate ion, the'most hydrophilic of the anionic functional groups. It is especialiy useful in the formulation of compositions for the treatment oE hair and skin because of its minimal tendencies to complex with metal ions and its minimal sensitivity to hard water.
' While the soil removal efficiency of the 'sulfated compounds oE this invention makes them suitable'for use in the formulation of aqueous hair shampoo compositions, it is necessary to enhance their foaming properties by the inclusion of low-irritating foam promoters taken from the group consisting of amine oxides of the general formula:

1 2 3 ~
The arrow is a conventional reDresentation of a semi-polar bond. These compounds are generall~ prepared by the direct oxidation o~ the approDriate tertiary amine. When Rl is a much longer chain the R2 and R3, the amine oxides have surEace activi-ty. For the purpose of this invention Rl is an alkyl group having from 1~ to 16 carbon atoms. Desirable surface active properties are lost if Rl is substantially less than 1 ms/~,~( s3~37 carbon atoms, and the compounds are insufficiently soluble if Rl is greater than 16 carbon atoms. R2 and ~3 are each selected from the group consisting of methyl and eth~l groups~
PreferabIy Rl is a dodecyl group or a mixture of dodecyl with decyl, tet'radecyl and hexadecyl, such that at least 50% of the groups are dodecyl groups. R2 and R3 are preferably methyl groups. A preferred amine oxide'for the purpose'of this invention is dodecyldimethylamine`oxide~
We have'found that in general from about 10 to 20%
of the sulfated condensation product should be employed along with'about 5 to 15% of the foam promoter. Conventional shampoo adjuvants may, of course, be employed in the formulation of shampoo compositions of this invention including other anionic, nonionic, or ampholytic surface active agents useful in modifying cleansing and foaming pro~erties as well as thickeners, perfumes, dyes and the li};e.

.... .. . ....
EXAMPLE I
__ .
To a three-neck flask equipped with stirrer~
thermometer, dropp~ing funnel and nitrogen inlet tube was added 100 grams (~ equivalent of OH) of PLURONIC~ L-61 (BASF
Wyando-tte Corp.) a polyoxypropylene-polyoxyethylene copolymer having a molecular weight of approximately 2000 and containing about 10% oxyethylene units on a molar basis. This was followed ~y the addition of 50~ grams of dioxane and 200 mL
of methylene chloride. To the dropping funnel was charged 11.6 grams (0.10 mole) of chlorosulfonic acid. The acid was slowly added to stirred solution and cooling applied to maintain a solution temperature of less than 25C. Upon completion of the addition of the acid, an additional 50 mL

j ~, ms/ ~

~9'~1~7 of methylene chloride was ~dded to the flask~ Then, and additional 1.2 grams of chIorosulfonic aci~ was added slo~ly through the'dropping funnel. The reaction flask contents were allowed to come ~o room temperature while being sparged with nitrogen to remove dissolved HCl.- The solution of the mono-sulfuric acid ester of the PLURONIC~ L-61 was then added to

4 grams of sodium hydroxide dissolved in one L of distilled water. Additional 10% aqueous sodium hydroxide was added to stabilize the pH at 8-9. The methylene chIoride and dioxane reaction solvents were'removed by distillation to yield an aqueous solution of PLURONIC~ L-61 monosulfuric!~sodium salt.

. .
EXAMPLE II
The disulfate, sodium salt of PLURONIC~ L-61 was prePared following the procedure employed in Example 1.
Using 100 grams of PLURONIC~ L-61, the polymer was disulfated with' 22.7 grams (0.2~ moles) of chlorosulfonic acid. After addition of the acid was complete, an additional charge of methylene chloride was made to the reaction vessel as previously described. Then 2.3 gra~s additional chIorosulfonic acid-was added. After warming to room temperature with'a nitrogen sparge, the reaction solution was poured slowly into a solution of 8 grams of sodium hydroxide dissolved in one L
of distilled water. Additional 10% aqueous sodium hydroxide was added to stabilize the pH at 8-9. The organic solvents were removed by distillation to give an a~ueous solution of PLURONIC~ L-61 disulfate, sodium salt.
EXAMPLE I'II
The following hair shampoo composition was prepared.

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Ingredient ' % by Weight Disulfated PI.URONIC~ L~61, sodium salt 1~.0 Aromox~DIlC (Akzona Inc.~'~a dimethyl-cocoamine 'oxide)' 10.0 Perfume, Perservative, color and Water qOs. to 100 - The''a~ove'shampoo was tested for soil removal efficiency (a measure of the cleansing power of the shampoo) and compared with'the efficacy of its individual com~onents as well as a commercial baby-shampoo. The' results are'shown below~
% Soil Removal - Ef~iciency at Shampoo Sy'stem -2 0 Concentration Disulfated PLURONIC~ L-61 24 Aromox~DMC 28 Shampoo of Example IV ' 33 Commercial Baby Shampoo 3~
The soil removal efficiencies exhibit a synergistic effect in the use of the mixture containing both the sulfated PLURONIC~ and the dimethylcocoamine foam promoter. Evaluation of the shampoo composition by panelists in a blind comparison -test showed thè shampoo to be effective in cleaning, lather, rinsing, appearance and feel. A persistant talc-likb'effect was noted on the skin and hair. Rabbit eye'irritancy tests showed the sulfated PLURONIC~ shampoo system to be of low irritation potential comparable to commeroial baby shampoos.
EXAMPLE V
Ingredient % by Weight Disulfated PLURONIC~ L~101, sodium salt 10.
3~ Ammonyx~CDO (Akzona Inc.) (a cocoamido ' propyl di~ethylamine oxide) 1~.0 Perfume preservative, color and water q.s. to 1 .

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.)~.. ~..'~92~7 EX~PLE VI
Ingredient % by Weight Monosulfated PLURONIC~ L-31, sodium salt 10.0 Aromox~DMC 10.0 Perfume, preservative, color and water q.s. to 100 Each oE the above two examples when employed as a hair shampoo provides the hair with adequate cleansing, manageability and cosmetic appearance with the benefit of a low level of skin and eye irritation.

- 10 -' ms/ '.~b

Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An aqueous hair shampoo composition containing about 10 to 20% by weight of (1) an anionic surface active agent comprising a sulfated condensation product of ethylene oxide with a base formed by condensing propylene oxide with propylene glycol and having a molecular weight of about 1100 to 4800, said condensation product having the structure:

HO-(C2H4O)x(C3H6O)y(C2H4O)z-H
where y is an integer from about 30 to 70, and (C2H4O)x+z equals about 5 to 20% of the total weight of the compound, in combination with (2) about 5 to 15% by weight of a foam promoter comprising an amine oxide of the general formula:

R1R2R3N ? O
wherein R1 is an alkyl group containing from about 10 to 16 carbon atoms and R2 and R3 are each selected from the group consisting of methyl and ethyl groups.

2. An aqueous hair shampoo composition as described in Claim 1 in which y is an integer from about 40 to 60.

3. An aqueous hair shampoo composition as described in Claim 1 in which (C2H4O)x+z equals about 7 to 13% of the total weight of the compound.

4. An aqueous hair shampoo composition as described in Claim 1 in which said condensation product of ethylene oxide with a base formed by condensing propylene oxide with propylene glycol has been reacted with 0.5 to 2.0 moles of sulfating agent per mole of condensation product.

5. An aqueous hair shampoo composition as described in Claims 1, 2 or 4 in which said amine oxide is dodecyldimethylamine oxide.